lacking in light; not bright or harsh; "a dim light beside the bed"; "subdued lights and soft music"
made dim or less bright; "the dimmed houselights brought a hush of anticipation"; "dimmed headlights"; "we like dimmed lights when we have dinner"
slow to learn or understand; lacking intellectual acuity; "so dense he never understands anything I say to him"; "never met anyone quite so dim"; "although dull at classical learning, at mathematics he was uncommonly quick"- Thackeray; "dumb officials make some really dumb decisions"; "he was either normally stupid or being deliberately obtuse"; "worked with the slow students"
lacking clarity or distinctness;
offering little or no hope; "the future looked black"; "prospects were bleak"; "Life in the Aran Islands has always been bleak and difficult"- J.M.Synge; "took a dim view of things"
become vague or indistinct; "The distinction between the two theories blurred"